I don't really find post-its that productive. You can't really get much down on them. Although I wouldn't have much use for them myself, I appreciate the things you can do with the S Pen, but I don't see myself doing anything like that on such a small screen. Just my opinion.
Lol, you should come to my office and see how many post its I use. But my life is making small, quick notes on files which my staff eventually acts on, or digitizes into the record. I've been able to tame and conquer that beast by using digital notes as I still use my Note 5 and surface pro 4 for such things in the office. On a personal level I'll highly miss the ability to do this, with the organizational might of OneNote it just made organizing things so much easier. I look at the small screen notes as part of a larger package of information which OneNote makes easy to catalogue and organize, then I can expand on it in a larger setting such as my SP4, laptop, desktop, etc. Then I can refer back to it in mobile format when I'm on the go.